1) Field of the Invention
The present invention relates to a technique of transmitting data between a mobile station (client) and a relay-station that are connected by a radio local area network (radio LAN).
2) Description of the Related Art
In a conventional radio communication apparatus, when a relay station receives data properly from a mobile station, an acknowledgement signal is returned to the mobile station, in order to secure continuity of data transmitted between the mobile station and the relay station. The relay station does not transmit the acknowledgement signal if it does not receive the data properly. When an acknowledgement signal is not received from the relay station, the mobile station stores the data in a memory and retransmits the data with the next data to be transmitted.
In a technique disclosed in Japanese Patent Application Laid-open No. 2002-112341, a relay station transmits an acknowledgement signal to a mobile station, for each data received from the mobile station. In this technique, however, efficiency of data transmission deteriorates because of additional transmission of the response signal. Moreover, communication load increases due to the need of transmitting each response signal, particularly when data are transmitted near a bandwidth limit, or when only a transmission environment of very low bandwidth can be secured. Furthermore, the communication may be broken due to the excessive transmission load.